1. Field of the Invention
The present invention relates to a chuck device for tool bits, and more particularly to a chuck device for tool bits that allows a tool bit to be mounted to and removed from the chuck device by a single hand.
2. Description of the Related Art
FIGS. 11 and 12 of the drawings illustrates a conventional chuck device for tool bits of a pneumatic device that includes an outer cover 90 biased by a spring 93. When a tool bit 94 is inserted into the chuck device, the user has to use one hand to move the outer cover 90 downward (as viewed from FIG. 11) to move a ball 92 to a position engaging with an annular recess 95 in the tool bit 94. Then, the outer cover 90 is released and the spring 93 is returned to retain the ball 92 in place. Nevertheless, when the tool bit 94 and/or the chuck device is subjected to a shock, the ball 92 is apt to be moved into an annular groove 91 of the outer cover 90 under the action of the spring 93. The tool bit 94 is thus disengaged. The present invention is intended to provide a chuck device that mitigates and/or obviates the above problems.